Introduction to Protos

Protos Increase Maintainability

Maintaining duplicates of information that should be the same is always risky. At application revision time, it can be very difficult to remember everywhere that the duplicates appear. Failing to update all copies, and thereby causing inconsistencies, is the motivating force behind programmers using symbolic constants (such as kNumberMinutesPerDay) rather than manifest constants (such as 1440). Having to change information in only one location, rather than in multiple locations, reduces program maintenance errors.

When you use protos, there is no fretting over multiple copies of information. You update slots in one location (the proto), rather than in multiple locations (a number of templates). Then all that remains is to rebuild the project in which the revised proto is used.


An online version of Programming for the Newton using Macintosh, 2nd ed. ©1996, 1994, Julie McKeehan and Neil Rhodes.

Last modified: 1 DEC 1996